Electrical motors are widely used for many different applications and are commonly used in domestic appliances. For example, in a vacuum cleaner a motor is used to drive a fan that causes dirty air to be sucked through a dirty air inlet. The dirty air passes through some form of separation device such as a cyclonic or bag separator that separates dirt and dust from the airflow, and finally the air is exhausted from an air outlet.
Switched reluctance machines have become increasingly popular in recent years. In a switched reluctance motor, a stator has sets of poles that are sequentially energised to rotate a rotor into line with the energised pair of poles, under the influence of the magnetic fields associated with each set of poles. By rapidly switching between different pairs of poles, it is possible to cause the rotor to rotate at a very high speed.
A bearing assembly is employed to rotatably support the shaft of the rotor with respect to the stator. A typical bearing assembly comprises a bearing, which comprises a plurality of ball bearings held between an inner race and an outer race, and a housing for supporting the bearing against the shaft of the rotor.
A problem which may be encountered with conventional bearing assemblies is that the pressure of the housing against the outer race of the bearing may cause the bearing to deform.